ORCA: fallback the locking clause #1052
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jiaqizho
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my-ship-it
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HuSen8891
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If the current GDD is closed and there is a `forupdate` statement, ORCA and planner does not need to generate a `LockRows` operator, expect the table is foreign table. However, if the current GDD is enabled, ORCA will generate a plan without the `LockRows` operator, which is a wrong plan. Supporting locking clauses in ORCA is a very difficult thing. Because ORCA does not fill `root->glob->paramExecTypes` in every operator, even if ORCA generates the `LockRows` operator, it may not working in the executor. For details, please refer to the EPQ(evalPlanQual) mechanism. Also I don't think ORCA should consider supporting locking clause. ORCA is an optimizer that is more biased towards OLAP scenarios. Support the EPQ mechanism will make ORCA more complex and more difficult to expand.
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Fixes #1031
What does this PR do?
If the current GDD is closed and there is a
forupdatestatement, ORCA and planner does not need to generate aLockRowsoperator, expect the table is foreign table. However, if the current GDD is enabled, ORCA will generate a plan without theLockRowsoperator, which is a wrong plan.Supporting locking clauses in ORCA is a very difficult thing. Because ORCA does not fill
root->glob->paramExecTypesin every operator, even if ORCA generates theLockRowsoperator, it may not working in the executor. For details, please refer to the EPQ(evalPlanQual) mechanism.Also I don't think ORCA should consider supporting locking clause. ORCA is an optimizer that is more biased towards OLAP scenarios. Support the EPQ mechanism will make ORCA more complex and more difficult to expand.
Type of Change
Breaking Changes
Test Plan
make installcheckmake -C src/test installcheck-cbdb-parallelImpact
Performance:
User-facing changes:
Dependencies:
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